1. Field of the Invention
The present invention relates to a pylon or tower mounted towing device whereby a towrope or tether is elevated high above a waterline, and aerodynamic forces, which may be coupled to the towrope or tether for stabilizing and/or steering a tow vehicle.
2. Description of the Related Art
Wakeboarding has become the modern gymnastics of watersports. Competitive wakeboarders score points by vaulting from the wake of a towboat and flipping, twisting, and grabbing high over the water""s surface. Higher, longer jumps are preferred. Towboats are modified to enhance the wakeboard experience and provide a better show for the spectators. Extra ballast is loaded into the boat and sometimes the hull is modified to form larger wakes. Superstructures such as pylons and towers extend upward from modern towboats to provide a higher towrope attachment. The higher attachment helps the rider to jump higher and stay up longer, but it sometimes has the adverse effect of rolling, and sometimes steering, the boat when the rider pulls hard outside the wake.
Several issues limit the practical height of the superstructure. The boat may need to be stored in a covered slip or shed where overhead clearance is limited. Ski or board racks, lights and/or stereo speakers may be mounted to the superstructure and should be accessible without climbing. The attachment point for the towrope should also be accessible without climbing. In the extreme case of a very tall superstructure on a small towboat, even the possibility of capsizing has limited the practical height of the superstructures to a height of about 7 feet.
A large population of 6-12 passenger towboats has emerged with extended pylons and towers furnished by the boat manufacturer or as an aftermarket accessory. Many of these larger family-sized vessels can support a tower or pylon extension well above 10 feet high without excessive rolling instability.
Much larger vessels, such as 30-50 foot sport fishing boats, are often equipped with much taller towers and sufficient speed to tow a wakeboarder, for example, but the bulky size, high cost, fuel consumption and awkward road handling make these impractical towboats.
When wakeboarding emerged as a trend-sport, tow pylons were extended to 6-10 feet above the water, and the thrust loads were transferred to the bow of the boat through the use of a forestay. The 6-10 foot high towers are now common, since they offer better lateral rigidity and speaker mounts. Correct Craft Inc. was issued a series of patents, which disclose various tower designs, towing methods and folding mechanisms.
Movable roll stabilizers are common on the hulls of larger vessels for the sole purpose of reducing the rolling action caused by unsteady seas. They are usually of the submersible type and act upon the hydrodynamic forces exerted as when a dorsal fin is rotated about an axis that is angled to nearly intersect the ship""s centerline. Mechanical actuators and a feedback loop control them.
The present invention extends the practical heights of the superstructures substantially above 10 feet for towboats of 25 feet or less in length. If needed for stability, an aerodynamic surface is deployed to counter the side force of the towed subject, keeping the boat safe and level.
More specifically, the present invention discloses an elevated tow device, comprising a superstructure extending skyward from a towboat, where the superstructure raises an attachment point of a tether above 10 feet from the waterline, and where the towboat is 25 feet or less in length; and a tether connecting the towboat to a towed subject.
In another embodiment, the device further comprises an aerodynamic surface, where the aerodynamic surface is held aloft to stabilize the superstructure. In a more preferred embodiment, the aerodynamic surface comprises a leading edge, a trailing edge, a sail area and means to link the aerodynamic surface with the tether.
In further embodiments, the aerodynamic surface is supported cord-wise with battens; the sail area further comprises aerodynamic slots; and/or the sail area is sized to counter rolling moments applied by the towed subject.
In another embodiment, the attachment point is elevated by a structure selecting from the group consisting of a mast, a pylon, an A-frame, a shroud line, a forestay, a bridge and a tower.
In yet another embodiment, the towed subject is selected from the group consisting of a wakeboarder, an hydrofoil rider, a knee boarder and a waterskier.
In further embodiments, the aerodynamic surface may be folded down for stowage or road travel; the folded down aerodynamic surface supports a shelter against weather; the folded down aerodynamic surface is fixed to the towboat so as to block out harmful sun rays or to protect a boat crew from adverse weather; and/or the aerodynamic surface is used for advertisements.
In other embodiments, a halyard is used to raise the tether into towing position; or a halyard is used to raise the tether and the aerodynamic surface together.
In yet another embodiment, the device further comprises a modular extension, where the modular extension is added to the superstructure to further raise the attachment point of the tether.
In another preferred embodiment, the elevated tow device comprises a superstructure extending skyward from a towboat; a modular extension connected to the superstructure, where the modular extension and superstructure raise an attachment point of a tether above 10 feet from the waterline, and where the towboat is 25 feet or less in length; and a tether connecting the towboat to a towed subject.